Theresa May and Nicola Sturgeon meet at Bute House in Edinburgh ©Andrew Milligan PA Archive/PA Images

It is reported that No. 10 is concerned about the possibility of Nicola Sturgeon announcing a second Scottish independence referendum at the same time that Theresa May triggers Article 50. Indeed, today Sturgeon told May that she has a “cast-iron mandate” to call one. Together with the looming prospect of direct rule being re-imposed in Northern Ireland this does look like a terrifying constitutional trifecta. Does the government really need to worry, though?

It is true that since its loss in the 2014 independence referendum, the Scottish National Party has electorally gone from strength to strength. Sweeping the board in Scotland in the 2015 General Election, leaving only three MPs from other parties—one each for Labour, the Lib Dems and the Scottish Tories. On the bounce it won government in the Scottish Parliament for a third term. And it now has high hopes for May’s council elections. But the real prize has always been a second referendum.

The nationalists get very upset if Scotland is ever called a one party state. The more relevant accusation here is that the SNP is a one purpose party. Independence at any costs. Every opportunity is taken to talk about a second referendum. And Brexit has provided a plethora of platforms for this. The strategy is clear: normalise the concept of a “neverendum”—the referendum that is held again and again until you get the right result—by sheer volume of repetition.

There are, however real obstacles in the way of a second referendum. First, there is the little matter of what the SNP told Scots the last time round. The Scottish Government White Paper it published said:

It is the view of the current Scottish Government that the referendum is a once-in-a-generation opportunity.

This was repeated by then First Minister Alex Salmond and his then deputy Nicola Sturgeon—there is a marvellous YouTube compilation of eight times when she makes this solemn promise.

Of course, like all normal politicians, Sturgeon reserves the right to break her promises. But that leads to the SNP’s second problem: it is an insurgent political force which, by definition, is not like all the rest. It is different. A new force. Except, apparently, when it comes to breaking its word.

Maybe this doesn’t matter. Perhaps it doesn’t matter that doomsday does not fall when the Leader says it will—the party simply recalibrates the date of the Apocalypse. Maybe the SNP will get away with it. Except that the public has no appetite for another referendum—and there has been no “Brexit bounce” in support for independence itself. That, in itself, should be a roadblock given that the much briefed SNP strategy of securing 60/40 support for independence before launching another campaign. The bigger roadblock, by far, is the third factor: prime minister Theresa May. She made her view on a second referendum absolutely clear when she met Nicola Sturgeon shortly after becoming PM:

“As far as I’m concerned, the Scottish people have had their vote, they voted in 2014 and a very clear message came through. Both the United Kingdom and the Scottish Government said they would abide by that.”

The Scottish Government wants to break that deal but it has admitted it does not have the power to legislate for a referendum—that was the whole point of the 2012 “Edinburgh Agreement.” A time-limited power was transferred to Holyrood explicitly on a one-off basis. The Scottish Government can huff and puff all it likes but without new Westminster legislation it will not have the ability to do anything other than polish yet another grievance.

So, the PM sees no case for a second referendum, the public don’t want it and the SNP has no power to legislate for one. Like her predecessor Margaret Thatcher, Theresa May is a lady “not for turning”—time for her to show some iron resolution.